Improvement in valves for steam-engines



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ANDREW BUCHANAN, OF JERSEY CITY, NEW JERSEY.

Specification forming part of Letters Patent No.

38,556, dated September 30, IBGQ; antedaied March 30, 1862.

To all whom, tm/Cty concern.-

Beit known that I, ANDREW BUCHANAN, of Jersey City, in the county of Hudson and State of New Jersey, have invented certain Improvements for the Relief ofthe Faces and Seats o the Slide-Valves of Steam-Engines froln Unnecessary Pressure; and I do hereby declare that the following is a full, clear, and exact description of the saine, reference being had to the accompanying drawings, forming part of this specilication, in which'- Figure lis a plan view of the valve-chest of a steam-engine with the cover removed to expose to view the valve and its appurtenances. Fig. 2 is alongitudinal section taken through the chest in the plane indicated by the line rv :v in Fig. l. Fig. 3 is a longitudinal section taken centrally through the valve'chest and valve. Fig. 4 is a transverse section taken through the chest in the plane indicated by the line y y in Figs. l and 3. Fig. 5 is a top view of the valve. f

Similar letters of reference indicate corresponding parts in the several figures.

This invention relates to transferring a desirable portion vof the pressure produced by the steam on the back of the valve to a series of rollers arranged to run upon tracks within the valve-chest. Y

It consists in a certain construction and arrangement of and means of adj usting the tracks upon which such rollers run; also, in certain means of combining the rollers with the valve and adjusting them relatively thereto.

To enable others skilled in the art to make and use my invention,I willproceed to describe its construction and operation.

a a is the valve-seat, in which the steamports b b and exhaust-port c are arranged in the manner common to engines which have but one valve for induction and eduction.

d is the iulet-port by which steam enters the valve-chestv from the boiler. Y

C is the valve, which may be of the common construction, but which is represented with its sides and ends corrugated, as shown at e e, to make them flexible and elastic, and which has a lip, n, at each corner to give it a greater length of bearing on the seat, for the prevention of its rocking, without interfering with the arrangement of the ports.

D is the yoke, applied to the valve in the usual manner, and E is the stem.

F F are the rollers, which partly lsupport screwsbeing rounded or otherwise so formed as to allow the bars G G to rock laterally in some degree, for the purpose ofadapting themselves to the peripheries of the rollers F F. By turning these'screws in the tapped holes in the bars the latter may be separately leveled lengthwise, and so adjusted relatively to each other and to the valveseat that the rollers running upon them (the face of the valve being properly adjusted to the rollers, as will be presently described) will keep the valve parallel with its seat both longitudinally and laterally, and so support it that it will n'ot press upon the seat sufficiently to produce any wear either of its own face or of the seat, and yet will work steam-tight. The bars G G are fur ther supportedat the middle of their length each by one of the two screws g g, which pass freely through fixed lugs h h on the interiors of the sides of the valve-chest, the heads of the said screws resting upon the tops of the said lugs; but these screws g g might be dispensed with by making the bars G G of sucient thickness to give them the necessary stiffness.

The rollers F F are arranged in pairs on axles' H H, square portions of which are fitted into recesses t t', of corresponding form, in the lower sides of the two bars I I, which are bolted by screw-bolts Z Z, or otherwise firmly secured on the top of the valve, close to the sides thereof, and which project over the ends of the valve for the reception of the axle; and these barshave tapped holes 'at the backs of the recesses t i for the recept-ion of set-screws j j, which serve to adjust the valvek relatively to the rollers so that its face will be parallel with the ways G G, and consequently parallel with the valve-seat as the rollers run upon the said ways, and the mode of combin- I ing the axles with the valve by the recesses i iin the bars I I allows the valve to be lifted from its seat in case of an accumulation of water in the cylinder or of great pressure occurring on the exhaust side of the piston in case of very sudden reversal ofthe engine with the cylinder full of steam. Sectors may be employed instead of rollers of complete circular form.

Thevalve and its appurtenances are adj usted before the cover L ofthe valve-chest is put on.

Vhen the valve is made with elastic sides, as shown at e e in Fig. 3, the ways G G are so adj nstedrelatively to the valve-seat by the screws e e g and the valve so adjusted to the rollers F F by means of the screws jj that the valve supported by the rollers running on the ways will allow every portion of the face of the valve to bear in some degree and uniformly on the seat, and when this has been done the screws e e are all turned down a uniform distance to raise the face of the valve from the seat. Vhen the pressure of the steam comes on the so-adjusted valve, it presses it down into contact with the seat, but yet does not press it -so hard thereon as to produce great friction or wear. Vhen the valve is of the usual kind, the adjustment by the screws is intended torbe such that the face will just touch the seat and work steam-tight thereon, but will work with very little friction.

The dexible elastic-sided valve does not require so extremely delicate an adjustment as that which is entirely rigid. Y By making the valve with a exible and elastic back the same result may be obtained as by its construction with flexible and elastic sides.

The advantages obtained by this invention over other modes of applying the rollers and their appendages consist, principally, in the facility afforded for extreme accuracy of adjustment of the valve.

I do not claim, broadly, transferring aportion of the pressure of the steam on the back of the valve to a series of rollers; but

Vhat I claim as my invention, and desire to secure by Letters Patent, is

1. The employment as ways for the valverollers to run upon of bars adjustable by screws, substantially as herein specified.

2. Combining the rolleraxles with the valve by means of recesses i i in thebars I I,or their equivalents, attached rigidly to and projecting over the ends of the valve, substantially as and for the purpose herein specified.

3. The set-screws jj,applied in combinationv with the bars I I,.or their equivalents, and the roller axles', substantially as and for the purpose herein specified.

ANDREW BUCHANAN.

Vitnesses:

JAMES LAIRD, CHARLEs HOLDEN. 

